An aeromagnetic survey was flown in the off-shore region NE of Cape Adare and the anomaly trends compared to on-shore structures between Pennell Coast and Tucker Glacier. The magnetic anomalies show two nearly orthogonal major trends. NNW-SSE trending anomalies NE of Cape Adare represent seafloor spreading within the Adare Trough. A connection of these anomalies to those in the Northern Basin of the Ross Sea is not clear. On both sides of the Adare Trough, NE-SW oriented ocean floor anomalies are probably related to structures causing the Hallett volcanics. On-shore faults are well aligned with off-shore anomalies. The main trends are NW-SE to NNW-SSE and NE-SW to NNE-SSW. NNW-SSE oriented dextral-transtensional to extensional faults parallel the Adare Peninsula and Adare Trough anomalies. NE-SW trending normal faults segmenting the main Hallett volcanic bodies are likely related to the aforementioned NE-SW anomalies.